1. Field of the Invention
The present invention relates to a tension-adjustable mechanism for the earpieces of a stethoscope. The present invention also relates to a stethoscope headset comprising this mechanism.
2. Brief Description of the Prior Art
A tension-adjustable mechanism for the earpieces of a stethoscope has been proposed in the following prior art patent:
U.S. Pat. No. 5,561,275 (Savage et al.) Oct. 1, 1996
According to this prior art mechanism, the two earpieces comprise respective weakened proximal end portions inserted side by side in a longitudinally movable sleeve. Longitudinal movement of the sleeve on the weakened end portions of the earpieces change the amplitude of the tension on the earpieces when these earpieces are spread apart from each other.
Although this prior art tension-adjusting mechanism is efficient, further adjustment capability is often required to meet with the requirements, needs and/or preferences of a wide range of users.
Therefore, need exists for a more versatile tension-adjusting mechanism capable of fulfilling the requirements, needs and/or preferences of a wide range of users.
In accordance with the present invention, there is provided a tension-adjusting mechanism for an elongated stethoscope earpiece having a proximal end. This tension-adjusting mechanism comprises a stethoscope neckpiece, a pivot mechanism portion, a spring mechanism portion, and a tension-adjusting mechanism portion. The pivot mechanism portion is interposed between the proximal end of the earpiece and the neckpiece, and defines a pivot axis about which the earpiece pivots relative to the neckpiece. The spring mechanism portion is interposed between the proximal end of the earpiece and the neckpiece, and comprises a spring member which deforms upon pivoting of the earpiece about the neckpiece in an outward direction. Deformation of the spring member produces a tension on the earpiece opposing to further pivoting of the earpiece in the outward direction. Regarding the tension-adjusting mechanism portion, it is interposed between the spring member and the neckpiece and defines a plurality of interchangeable point of contacts with the spring member. These points of contacts with the spring member have different positions relative to the neckpiece.
The above mentioned pivot mechanism portion, spring mechanism portion, and tension-adjusting mechanism portion provide for the level of versatility required to fulfill the requirements, needs and/or preferences of a wide range of users.
Preferably, the pivot mechanism portion comprises abutment surfaces restricting, by abutment, free pivotal movement of the earpiece about the neckpiece within given limits.
According to other preferred embodiments of the tension-adjusting mechanism:
the pivot mechanism portion comprises a pivot pin pivotally mounted on the neckpiece, and a pivot tube pivotally mounted on the pivot pin and connected to the proximal end of the earpiece;
the spring member comprises a resilient blade having one end formed with the pivot pin;
the pivot tube has an open, axial slot through which the resilient blade extends when the pivot pin is inserted in that pivot tube, the resilient blade has a thickness, and the slot has a width larger than the thickness of the blade to allow limited pivotal movement of the pivot tube about the pivot pin; and
the pivot tube has an annular end face provided with a lug, the neckpiece has a pair of abutment surfaces situated on opposite sides of the lug, and the lug abuts on either abutment surface to restrict pivotal movement of the pivot tube about the neckpiece within predetermined limits.
The present invention further relates to a headset for electronic stethoscope, comprising first and second elongated stethoscope earpieces each having a proximal end, and the above described tension-adjusting mechanism for each elongated stethoscope earpiece.
Preferably, the stethoscope neckpiece is common to both the first and second elongated stethoscope earpieces, the neckpiece comprises a hollow shell formed with openings for the proximal ends of the earpieces, and the hollow shell comprises a front shell portion and a rear shell portion assembled together to form that hollow shell.
In accordance with a preferred embodiment:
the resilient blade associated to the first earpiece has a first distal end section opposite to the pivot pin;
the resilient blade associated to the second earpiece has a second distal end section opposite to the pivot pin;
the tension-adjusting mechanism portion associated to both the first and second earpieces comprises a tension-adjusting cam having a geometrical axis, rotatable about this geometrical axis and lockable in either first, second and third angular positions;
the tension-adjusting cam comprises an axial member having an outer tubular surface and two first points of contact with the first and second distal end sections, respectively, formed by two points of this outer tubular surface, respectively, when the tension-adjusting cam is locked in the first angular position;
the axial member of the tension-adjusting cam comprises, on its outer tubular surface, first and second diametrically opposite, axial and radial fins of intermediate height having respective first and second free axial edge surfaces, and two second points of contact with the first and second distal end sections, respectively, formed by these first and second free axial edge surfaces of the first fin, respectively, when the tension-adjusting cam is locked in the second angular position;
the axial member of the tension-adjusting cam comprises, on its outer tubular surface, third and fourth geometically opposite, axial and radial fins of larger height with third and fourth free axial edge surfaces, respectively, and two third points of contact with the first and second distal end sections, respectively, formed by these third and fourth free axial edge surfaces of the second fin, respectively, when the tension-adjusting cam is locked in the third angular position;
the neckpiece comprises a hole with peripheral notches, and the tension-adjusting cam comprises lugs engaging the peripheral notches of the hole in the neckpiece to lock the tension-adjusting cam in either the first, second and third angular positions; and
the tension-adjusting mechanism associated to both the first and second earpieces comprises a spring element interposed between the neckpiece and the tension-adjusting cam and spring biasing the lugs of this tension-adjusting cam in the notches of the hole in the neckpiece, whereby, to be rotated, the tension-adjusting cam is moved against the spring-biasing force produced by the spring element to disengage the lugs from the notches and is rotated and then released to engage the lugs with other notches.
The foregoing and other objects, advantages and features of the present invention will become more apparent upon reading of the following non-restrictive description of a preferred embodiment thereof, given for the purpose of illustration only with reference to the accompanying drawings.